1. Field of the Invention
The present invention relates to an active matrix organic light-emitting diode (OLED) display and in particular to a less costly and easily manufactured active matrix OLED display.
2. Description of the Related Art
Organic light-emitting diodes (OLED) are active lighting elements, which, when receiving a voltage, inject an electron into an organic semiconductor through a cathode, and into an electron hole through an anode. The electron and the electron hole form an electron-hole pair in an organic thin film, and produce photons by radiative recombination.
Compared with a conventional inorganic LED, the OLED is easily formed on large panels. As well, displays utilizing OLEDs require no backlight module, such that process is simpler and costs are reduced.
OLEDs can be applied to small panels such as those in personal digital assistant (PDA) or digital camera applications.
In conventional OLED display, a pixel is formed by two thin film transistors (TFT). The first TFT switches the pixel, and the second TFT controls the power applied to the OLED. Two types of common TFTs are applied to OLED displays, amorphous silicon thin film transistor (a-Si TFT) and low-temperature Poli-silicon (LTPS) TFT. The carrier mobility of the LTPS TFT is 100 times that of a-Si TFT, such that the LTPS TFT can supply the OLED with sufficient current, making it a better choice as a control element of the active matrix OLED display. However, manufacture of the LTPS TFT is very complicated, lowering product reliability and increasing costs.